<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>margin问题4</title>
    <style>
        *{margin: 0;padding: 0;}
        .d1{
            width: 800px;
            height: 300px;
            background-color: rgb(64, 190, 77);
        }
    </style>
</head>
<body>
    <div class="d1"></div>

</body>
</html>